Histone deacetylase (HDAC) inhibitors (HDACi) and mechanistic target of Rapamycin (mTOR) inhibitors (mTORi) are known anti-cancer agents. The combined use of these agents is known to have anti-cancer efficacy against certain neoplasm subtypes; however, this combined treatment is not efficacious in all neoplasm subtypes, and is not efficacious against all neoplasms within a particular subtype.